This invention relates generally to a power transfer mechanism incorporating a planetary gear set. More particularly, it relates to a planetary gear set including differential means for proportioning torque between a plurality of output elements in one operating condition thereof and for providing locked-up reduction drive in another operating condition thereof.
In recent years, there have been many improvements in power transfer mechanisms, including improvements relating to planetary gearing for establishing paths for the transfer of power in high and low-range modes. Some such planetary gear sets provide torque proportioning in one operating range and direct drive in another operating range. Still other planetary gear sets provide direct and reduction drive operating ranges without the provision of torque proportioning. The gear sets generally are shifted by engaging and disengaging friction elements manually, hydraulically, electrically or by some other suitable means. Generally this has required considerable space and a large number of parts within the assembly.
There remains a need to provide a planetary gearing system which combines the torque proportioning feature in one operating range and locked-up reduction drive in another operating range, which system is compact and easy to manufacture and assemble.